ABSTRACT
Soil chemistry is usually divided into two divisions: reactions attributed directly to biochemical (microbial) activity, and those reactions which are abiotic. Mobile elements (as ions) migrating with soil water are often retained by soil particles. The processes responsible for retention may be categorized into those which incorporate the element into the crystal structure of the mineral or attach it to the surface (or near surface) of soil grains. Mobility of elements in soil is the result of the extent of fixation, complex formation, and reaction kinetics. Eh/pH diagrams yield important information regarding the potential fixation of an element in soil. The Eh or pH of a soil can be altered to promote fixation of contaminants. If the available water has an Eh/pH potential which encourages dissolution, the soil minerals will be more easily weathered. Soil colors are good indicators, but subtle differences are difficult to compare between samples. Individual investigators have varying perceptions of color.
